REQUESTS to "adhere" to instructional signs are spreading. Hugh Carter was told in Toronto, Canada, that he "must adhere to traffic personnel" (14 December 2013). Now Henry Shipley informs us that carriages run by Arriva Trains Wales contain no-smoking signs with the rider that "Failure to adhere to this notice may result in prosecution." What a quandary: risk arrest or get well and truly stuck on a train?